"It's A Trap!" is a catchphrase that is often used as a reaction image to photos of transsexuals and crossdressers (often referred to as "traps"), or people who appear sexually ambiguous. It usually means that the person in question has male reproductive organs, regardless of their appearance. Though less frequently, the phrase can be also used as a warning of any potential danger. In addition, the quote as it appears in the film has been widely regarded by the fans of Star Wars as one of the most famous and beloved lines from the original trilogy.
The phrase stems from a memorable quote said by Admiral Ackbar (voiced by Erik Bauersfeld), the leader of Mon Calamari rebels, during the Battle of Endor in the 1983 Star Wars film Episode VI: Return of the Jedi. In the movie, as the Alliance mobilize its forces in a concerted effort to destroy the Death Star, Admiral Ackbar encounters an unexpected ambush, which leads him to exclaim, "It's a trap!"
Admiral Ackbar: "Take evasive action. Green Group, stay close to holding sector MD-7."
Crewman: "Admiral, we have enemy ships in sector 47!"
Admiral Ackbar: "It's a trap!"
Sometime in the early 2000s, Something Awful administrator OMGWTFBBQ created and uploaded an image macro based on a screenshot of Admiral Ackbar from Return of the Jedi with the caption that reads "IT'S A TRAP."
According to various accounts, the image macro soon became adopted as a popular reaction image used to warn others of a potential bait-and-switch prank ahead, and by mid-to-late 2002, the phrase had made its way to FARK and continued to gain traction as a running joke in Photoshop Phriday threads. Beginning in 2004, the joke spawned hundreds of parody sites featuring the soundbite of Admiral Ackbar's quote on YTMND, with the most notable instance uploaded by user MultiKoopa on June 2nd, 2005, which has garnered more than 313,000 views (as of April 2016). Around the same time, shortly after the launch of the imageboard community 4chan, the phrase became closely associated with traps, a slang term for a photograph of a model or illustration of an anime character wherein the gender of the subject seems to be ambiguous or androgynous in appearance. Following the launch of YouTube in 2005, more than a thousand fan-made videos that prominently feature or parody Admiral Ackbar's line and the extended dialogue were uploaded to the video sharing site. On May 20th, 2009, an Urban Dictionary entry was created for the phrase:
A phrase based on a misspelling of "It's a trap" a phrase and meme said by Ackbar in Star Wars Episode VI. It is popularly used sarcastically on message boards and chan sites.
/b/tard #1: It's a trap!
/b/tard #2: No! It's a tarp!
Star Wars: The Force Unleashed
In the Nintendo Wii version of LucasArts' action-adventure video game Star Wars: The Force Unleashed, released on September 16th, 2008, Admiral Ackbar can be played as a hidden character if the player enters the cheat code "ITSATWAP."
"It's a TARP!"
"It's a Tarp!" is an intentional misspelling that spawned one of the more frequently posted derivatives. According to Google Trends, search queries for "it's a tarp" picked up in April 2008. Several months later, the Obama administration's introduction of the "Troubled Asset Relief Program," shortened as TARP, inspired a batch of additional derivatives.
On Comedy Central
On February 11th, 2010, footage of Admiral Ackbar reciting the line was featured in two separate segments on Comedy Central's The Daily Show and The Colbert Report, wherein the soundbite is intercut with news reel clips of Republican leaders describing an invitation to President Barack Obama's health care summit as a "trap."
On Family Guy
On December 21st, 2010, American animated TV series Family Guy released a direct-to-video special episode titled "It's a Trap," which retells the story of Star Wars: Return of the Jedi, as the final chapter of the show's Star Wars parody trilogy, with the other two being "Laugh It Up" and "Fuzzball." On May 22nd, 2011, Fox aired the hour-long special as the double-episode finale of Family Guy's ninth season.
 Hollywood Reporter – Erik Bauersfeld, Admiral Ackbar Voice Actor in 'Star Wars' Films, Dies at 93